tst/memoize.test.ts


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import { memoize } from '@emprespresso/pengueno';

interface RefCounter {
    inc(by: number): number;
}

test('memoizes', () => {
    let _c = 0;
    const c: RefCounter = {
        inc(by: number): number {
            _c += by;
            return _c;
        },
    };

    const incBy = memoize((n: number) => c.inc(n));

    expect(incBy(1)).toBe(1);
    expect(incBy(2)).toBe(3);
    expect(incBy(20)).toBe(23);
    expect(incBy(20)).toBe(23);
    expect(incBy(1)).toBe(1);
    expect(incBy(2)).toBe(3);
});